Difference Between Cushing Disease and Cushing Syndrome

Main Difference – Cushing Disease vs Cushing Syndrome

All of us face various stressful situations in our day to day life. Cortisol is the hormone which is responsible for regulating the responses towards stress. ACTH hormone, produced by our pituitary gland, stimulates the production as well as the release of Cortisol and when the proper regulation of this process goes out of control, it results in an over production of the hormone. Cushing disease and Cushing syndrome are two endocrine conditions which take place due to over production of a-fore mentioned Cortisol. Cushing disease is caused by a tumor or an excessive growth in the pituitary gland and the disease is a major cause of the Cushing syndrome. This is the main difference between Cushing disease and Cushing syndrome.

Here, we will be discussing,

1. What is Cushing Disease?
– Cause, Signs and symptoms, Diagnosis, Treatment and Follow-up

2. What is Cushing Syndrome?
– Cause, Signs and symptoms, Diagnosis, Treatment and Follow-up

3. What is the Difference between Cushing Disease and Cushing Syndrome?

What is Cushing Disease?

Cushing disease is characterized by the over production of ACTH hormone from the pituitary gland and is known to be one of the major causes of Cushing syndrome. Being a very rare condition, affecting only 10-15 people in a million, this has a significant female predominance and is most often seen in individuals between 20-50 years of age.

This disease is usually caused by a tumor or an excessive growth of the pituitary gland and Adenoma, a benign tumor of the gland, is known to be one of the major initiative factors. This tumor will start releasing excessive amounts of ACTH which will, in turn, release Cortisol and result in an augmented metabolism of carbohydrates, fats, and proteins and reduce possible inflammation.

Signs and Symptoms of Cushing Disease

Obesity above the waist (upper body) with thin upper and lower limbs.
Moon-like face- full, round and red
Growth retardation in children
Acne
Skin infections
Purple striae (marks) on the skin of abdomen, thigh, and breast
Easy bruising especially on the skin of arms and hands
Backache on exertion
Buffalo hump- fat deposition between shoulders
Muscle weakness
Bone pain and tenderness
Excessive hair growth on the body
Irregular periods
Reduced libido
Impotence
Unexplained headache
Increased frequency of urination

Diagnosis, Treatment and Follow-up

The diagnosis of Cushing disease can be made by a complete clinical history along with a thorough physical examination to see the presence of above-mentioned signs and symptoms.

However, further investigations can be carried out to confirm the excessive levels of Cortisol in the body:

24 HOUR- urine test for Cortisol
Low dose Dexamethasone suppression test
Salivary Cortisol test (late night and early morning samples)

To identify the cause:

Blood ACTH levels
Brain MRI to exclude pituitary tumors
Corticotrophin-releasing hormone test
High dose Dexamethasone Suppression test
Inferior Petrosal sinus sampling (IPSS)

To exclude any associated illnesses:

Fasting blood sugar levels and HBA1c
Lipids and Cholesterol levels
Bone mineral density to exclude Osteoporosis

As far as the treatment for Cushing disease is concerned, the surgical removal of the pituitary tumor is the treatment of choice. However, this may be postponed depending on the severity of the condition. After the surgery, the pituitary gland will slowly start working in a healthy manner, as per required.

During the recovery, patients will be prescribed with Cortisol replacement therapy, since it will take quite a long time for the gland to start producing ACTH.

In case the tumor is not removed completely due to a certain reason, radiation therapy is indicated in order to suppress the augmented activities slowly.

If the tumor doesn’t respond to surgical or radiation therapy, patients will have to use anti-cortisol medicines to stop the production of Cortisol in the body.

Untreated Cushing disease can result in various other complications such as,

Compression fractures
Hypertension
Diabetes
Kidney stones
Infections
Psychiatric conditions

What is Cushing Syndrome

This is an endocrine condition, where the body produces an increased amount of Cortisol due to several health disturbances such as,

Exogenous Cushing Syndrome as a result of too much Glucocorticosteroid intake (prednisolone, Dexamethasone) to treat diseases like Asthma, inflammatory bowel disease, malignancies, joint pain etc.
Cushing disease
Adrenal gland tumor
Tumor producing Corticotrophin – Releasing Hormone (CRH)
Ectopic Cushing syndrome – Releasing excessive ACTH

Signs and symptoms of Cushing syndrome are similar to those of the Cushing disease and they are diagnosed in the same manner in order to identify an excessive presence of Cortisol in the body and possible complications.

The treatment modality for Cushing syndrome mainly depends on the etiology.

Patients who develop this following an excessive usage of corticosteroids are advised to decrease the medicinal dosage slowly and stop it. In cases where it is impossible to stop the dosage due to chronic ailments (diabetes, hypertension), the levels of cortisol should be closely monitored to identify any possible adverse effects.

If diagnosed with a pituitary tumor, removing it surgically or treating with radio-therapy followed by cortisol replacement.

Anti-cortisol releasing medicines for patients whose tumor cannot be removed.

Both Cushing disease and Cushing syndrome occur due to an endocrine disturbance of the body-particularly caused by an excessive secretion of Cortisol hormone.

Cushing disease is one of the major causes of Cushing syndrome and predisposed by a pituitary tumor or Adenoma of the brain.

On the other hand, Cushing syndrome can have multiple causes including Cushing disease as well as long term intake of corticosteroids, ectopic tumors releasing CRH etc.

Both conditions are diagnosed in a similar way; the treatment of Cushing disease involves the surgical removal or radiotherapy of the tumor and Cushing syndrome is managed according to the root-cause, as described above.

Image Courtesy:

“Cushing syndrome” By Mikael Häggström – Own work (CC0) via Commons Wikimedia